Definition:Rank (Linear Algebra)

From ProofWiki
Jump to navigation Jump to search

Definition

Linear Transformation

Let $\phi$ be a linear transformation from one vector space to another.

Let the image of $\phi$ be finite-dimensional.


Then its dimension is called the rank of $\phi$ and is denoted $\rho \left({\phi}\right)$.


Matrix

Let $K$ be a field.

Let $\mathbf A$ be an $m \times n$ matrix over $K$.


Then the rank of $\mathbf A$, denoted $\rho \left({\mathbf A}\right)$, is the dimension of the subspace of $K^m$ generated by the columns of $\mathbf A$.


That is, it is the dimension of the column space of $\mathbf A$.